A jaw of the abovementioned type is described for example in Austrian Pat. No. 315 041 (corresponds to U.S. Pat. No. 3,822,071). The movable part of this design is constructed in the form of a rack having a body of revolution with at least one annular groove therein and is movably supported in the longitudinal center plane of the jaw between the bolts of the sole holders with extensions on the sole holders being received in the grooves of the rack. If a lateral force acts onto a clamped ski shoe, both sole holders swing outwardly and the rack is hereby pulled backwardly by the extensions against the force of the spring. An important disadvantage of this conventional design is that high frictional forces develop between the ski shoe sole and the sole holder during a load on the sole holder in a direction toward the tip of the ski, as will occur for example during a fall of the skier forwardly, which frictional forces delay or prevent a release of the jaw and can result in injury (fractures) to the skier.
Therefore, the purpose of the invention is to bring help here and to provide a jaw of the abovementioned type in such a manner that said jaw compensates for the frictional forces which occur during the application of a force which acts onto the jaw in a direction toward the tip of the ski and wherein the release force is to be maintained constant.
The set purpose is inventively attained by a support member being movably guided in the longitudinal direction of the ski, and the arms of the two sole holders, which arms extend in a direction toward the longitudinal axis of the ski being supported ski-fixed. Through these measures, a compensation of the additional frictional forces which occur between the sole holders and the ski shoe during a forward fall of the skier is assured. The ski shoe moves the support member in direction toward the tip of the ski, the ski-fixed supported sole holder arms swing forwardly during a simultaneous compression of the spring and facilitate an easier release of the ski shoe compared with common jaw systems while maintaining the lateral release force constant. Also the inventive measures prevent a deformation of the ski shoe during a bending of the ski, as it occurs for example during skiing through a depression.
To support the sole holder arms, a support part is inventively provided which is moved onto a ski-fixed elongated guide rail extending longitudinally of the ski, which support part is supported at one end on at least one stop pin on the guide rail and at the other end by means of two support arms which extend substantially parallel with respect to the upper side of the ski and symmetrically with respect to the longitudinal axis of the ski and engage the sole holder arms. The structural part which is provided for supporting the sole holder arms is thus designed very simply. Further, it can easily be arranged in the jaw and requires little or no structural changes to existing jaw systems.
An important advantage of the invention is in the location of the points of engagement of the support arms of the support part on the arms of the sole holders relative to the longitudinal axis of the ski for determining the degree of translation of a power component, which acts in a direction toward the tip of the ski onto the sole holder, onto the spring force. The degree of translation of a force, which force acts in a direction toward the tip of the ski onto the sole holder, onto the spring force can thus be freely chosen by the designer in correspondence with the respectively desired spring.
A further inventive development is characterized by the support member having a support plate which is movable on a ski-fixed guide rail and an upstanding wall segment thereon which extends substantially perpendicularly with respect to the upper side of the ski. The upstanding wall segment supports an end of the spring remote from an adjustable abutment and has on both sides of the longitudinal axis of the ski a recess receiving therethrough one of the support arms of the support part. These measures contribute to the compact design of the jaw.
A further characteristic of the invention is in the support member being movably guided on the guide rail in an area which corresponds with the spacing of the upstanding wall segment on the support member from the support part, which upstanding wall segment faces the support part. This measure prevents a movement of the support member toward the tip of the ski beyond acceptable limits. Further, a lateral holding force and thus a lateral release force for a ski shoe which is inserted into the jaw is assured on the sole holders even when the force which acts onto the sole holders in a direction toward the top of the ski is relatively large. A further preferable development of the invention is in providing a part which is movable against the force of the spring in a longitudinal direction of the ski and functioning as a release plate which preferably has a window therein for indicating the adjusted spring force. This release plate also has a bent section engaging the arms of the sole holder. A draw rod is provided coaxially with respect to the spring with one end thereof being secured to the bent section of the release plate and the other end being rotatably supported in an adjusting screw. With this structure, a purely horizontal release is assured and with a desired constant release force.